The invention provides a cushioning mechanism comprising a base, an equal-width cam mechanism, a limiting bracket, a ball screw, two groups of energy dissipaters and energy dissipater fixing bases, wherein the equal-width cam mechanism, the limiting bracket, the ball screw, the two groups of energy dissipaters and the energy dissipater fixing bases are mounted on the base. The equal-width cam mechanism comprises a quadrilateral frame and a cam mounted in the quadrilateral frame. The cam is connected with a nut of the ball screw. The two groups of energy dissipaters are mounted on the energy dissipater fixing bases on the two sides of the equal-width cam mechanism separately. The ends, away from the energy dissipater fixing bases, of the two groups of energy dissipaters are connected with the two sides of the quadrilateral frame separately. The invention is low in manufacturing cost and good in buffering and limiting effect.